Thanks to its anaerobic engines, the Kronstadt will be able to stay submerged for weeks and be less exposed than conventional diesel-electric subs.
Air-independent (closed cycle) submarines usually use hydrogen-oxygen fuel cells and are quieter compared to the diesel-electric boats that exist today.
The Russian-designed air-independent power plant (AIP) differs from its foreign analogues in that it obtains hydrogen within itself by reforming the onboard diesel fuel.
They can be effectively employed against both surface ships and submarines.
There are currently over 50 AIP submarines in service around the world, with the number likely to double in the coming decade.